The Design Wizard does apply some maximum image size and file size constraints to uploaded logos. By default, the maximum constraints within the Design Wizard are
You can upload a logo larger than these dimensions through the Design Wizard. The image will be proportionally resized to fit within the maximum dimensions. If you wish to use a larger size image, you can increase the maximum dimensions in the Store Editor.
To increase the logo constraints:
When you upload an image to the Name-image variable, that image will now resize only if the uploaded image is larger than the maximum dimensions you have set.